# Insertion in binary search tree without recursion in python

Python program for Insertion in binary search tree without recursion. Here problem description and other solutions.

```
# Python 3 program for
# iterative insert in binary search tree
class TreeNode :
def __init__(self, data) :
self.data = data
self.left = None
self.right = None
class BinarySearchTree :
def __init__(self) :
self.root = None
# insert a element
def addNode(self, data) :
# Create a new node
node = TreeNode(data)
if (self.root == None) :
# When adds a first node in bst
self.root = node
else :
find = self.root
# Add new node to proper position
while (find != None) :
if (find.data >= data) :
if (find.left == None) :
# When left child empty
# So add new node here
find.left = node
return
else :
# Otherwise
# Visit left sub-tree
find = find.left
else :
if (find.right == None) :
# When right child empty
# So add new node here
find.right = node
return
else :
# Visit right sub-tree
find = find.right
# Display preorder
def preorder(self, node) :
if (node != None) :
# Display node value
print(" ", node.data, end = " ")
# Visit to left subtree
self.preorder(node.left)
# Visit to right subtree
self.preorder(node.right)
def inorder(self, node) :
if (node != None) :
# Visit to left subtree
self.inorder(node.left)
# Display node value
print(" ", node.data, end = " ")
# Visit to right subtree
self.inorder(node.right)
def postorder(self, node) :
if (node != None) :
# Visit to left subtree
self.postorder(node.left)
# Visit to right subtree
self.postorder(node.right)
# Display node value
print(" ", node.data, end = " ")
def main() :
tree = BinarySearchTree()
# 10
# / \
# / \
# 4 15
# / \ /
# 3 5 12
# -------------
# Build binary search tree
tree.addNode(10)
tree.addNode(4)
tree.addNode(3)
tree.addNode(5)
tree.addNode(15)
tree.addNode(12)
# Display tree nodes
print("Preorder ")
tree.preorder(tree.root)
print("\nInorder ")
tree.inorder(tree.root)
print("\nPostorder ")
tree.postorder(tree.root)
if __name__ == "__main__": main()
```

**Output**

```
Preorder
10 4 3 5 15 12
Inorder
3 4 5 10 12 15
Postorder
3 5 4 12 15 10
```

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